ironass
Extreme Android User
One of the features of the Samsung Galaxy S4, GT-i9505, quad core phone that I use a lot is GPS and Google Maps. Both for work and play. In fact, I've been using phone based GPS since my Nokia N80 days, some 7 years ago.
However, the GPS and Google Maps on my Galaxy S4 in the UK knocks spots off of anything I've tried before, including my previous phone, the Galaxy S2.
The S4 can pick up around 25 satellites very quickly and offers me a fix of within 3m, (9.84ft), in around 10 sec's or so on a clear day, outdoors. This compares to the Galaxy S2 which would pick up about 12 satellites and take slightly longer for a fix.
In fact, so good is the S4 with GPS that I have abandoned using dedicated GPS equipment.
In my own home the GPS can even detect the part of the house I am in with a slightly longer fix time.
For anyone who is experiencing GPS location and/or fix time problems, there are a couple of things that you can do which may help... although it will not fix a broken/damaged GPS antenna or improve your GPS if your government offers a degraded or non existent service.
1. On your phone go to Settings > More > Location services and ensure that Access to my location is set to ON and that Use GPS satellites and Wi-Fi & mobile network are both checked. In Google Maps, go to Menu > Settings > Google location settings and ensure that Access location is checked.
2. Download GPS Status & Toolbox, free from the Play Store. There is a paid version but the free one will suffice.
3. In GPS Status & Toolbox, go to Menu > Settings > GPS & Sensors > Auto-download AGPS data and choose how often you wish AGPS to be updated. I use once a day. You may decide more or less. Also Sensor filtering. I have mine set to weak but you can experiment. A stronger filter increases the GPS fix time a bit.
4. Other settings you can choose to suit yourself and your location, such as meters/feet, miles/kilometers, etc: Unrooted users - go to #6
5. For rooted users only. (Not necessary) Download FasterGPS, free from the Play Store and select your location. This now tells your GPS to use a local location service which can speed up your fix time. See Hawker's post, #6, below for more information.
6. Now take your phone outside, away from buildings if possible and with a clear view of the sky. Open GPS Status & Tools > Menu > Tools and select both Compass calibration and Calibrate pitch and roll and follow the instructions for calibration.
7. Now, still outdoors, put your phone into Flight Mode so that the phone is only using its internal GPS for a fix and go to Menu > Tools Manage A-GPS state > Reset and then leave it for around 20 minutes on a flat surface.
8. After around 20 minutes, very carefully, turn Flight Mode off and in Menu > Tools > Manage A-GPS state > Download
9. Now either, rotate the phone a couple of times through its three axis or do some figures of 8 with the phone.
10. Go to Google Maps in Satellite mode and see how quickly you get an accurate fix.
Because I am a heavy GPS user, I tend to do this once every month or two but for most peoples uses, once every three or four months should suffice, if that.
Below is a screenshot of Google Maps in Satellite mode showing a local Ordanance Survey, "Trig Point". To show the plinth the trig point was on, I had to move slightly sideways as the blue location dot was covering it completely. This was with no Wi-Fi and on EDGE.

This is a screenshot, taken at the same time, of GPS Status & Toolbox's, (Pro), readout showing a lock on 25 out of 26 satellites and a margin of error of around 3m/10ft, in fact it was so spot on I had to move to show the white plinth.

Since all the apps I have mentioned are free, you have nothing to lose by trying it. Hope it helps!
However, the GPS and Google Maps on my Galaxy S4 in the UK knocks spots off of anything I've tried before, including my previous phone, the Galaxy S2.
The S4 can pick up around 25 satellites very quickly and offers me a fix of within 3m, (9.84ft), in around 10 sec's or so on a clear day, outdoors. This compares to the Galaxy S2 which would pick up about 12 satellites and take slightly longer for a fix.
In fact, so good is the S4 with GPS that I have abandoned using dedicated GPS equipment.
In my own home the GPS can even detect the part of the house I am in with a slightly longer fix time.
For anyone who is experiencing GPS location and/or fix time problems, there are a couple of things that you can do which may help... although it will not fix a broken/damaged GPS antenna or improve your GPS if your government offers a degraded or non existent service.
1. On your phone go to Settings > More > Location services and ensure that Access to my location is set to ON and that Use GPS satellites and Wi-Fi & mobile network are both checked. In Google Maps, go to Menu > Settings > Google location settings and ensure that Access location is checked.
2. Download GPS Status & Toolbox, free from the Play Store. There is a paid version but the free one will suffice.
3. In GPS Status & Toolbox, go to Menu > Settings > GPS & Sensors > Auto-download AGPS data and choose how often you wish AGPS to be updated. I use once a day. You may decide more or less. Also Sensor filtering. I have mine set to weak but you can experiment. A stronger filter increases the GPS fix time a bit.
4. Other settings you can choose to suit yourself and your location, such as meters/feet, miles/kilometers, etc: Unrooted users - go to #6
5. For rooted users only. (Not necessary) Download FasterGPS, free from the Play Store and select your location. This now tells your GPS to use a local location service which can speed up your fix time. See Hawker's post, #6, below for more information.
6. Now take your phone outside, away from buildings if possible and with a clear view of the sky. Open GPS Status & Tools > Menu > Tools and select both Compass calibration and Calibrate pitch and roll and follow the instructions for calibration.
7. Now, still outdoors, put your phone into Flight Mode so that the phone is only using its internal GPS for a fix and go to Menu > Tools Manage A-GPS state > Reset and then leave it for around 20 minutes on a flat surface.
8. After around 20 minutes, very carefully, turn Flight Mode off and in Menu > Tools > Manage A-GPS state > Download
9. Now either, rotate the phone a couple of times through its three axis or do some figures of 8 with the phone.
10. Go to Google Maps in Satellite mode and see how quickly you get an accurate fix.
Because I am a heavy GPS user, I tend to do this once every month or two but for most peoples uses, once every three or four months should suffice, if that.
Below is a screenshot of Google Maps in Satellite mode showing a local Ordanance Survey, "Trig Point". To show the plinth the trig point was on, I had to move slightly sideways as the blue location dot was covering it completely. This was with no Wi-Fi and on EDGE.

This is a screenshot, taken at the same time, of GPS Status & Toolbox's, (Pro), readout showing a lock on 25 out of 26 satellites and a margin of error of around 3m/10ft, in fact it was so spot on I had to move to show the white plinth.

Since all the apps I have mentioned are free, you have nothing to lose by trying it. Hope it helps!